Screwdrivers and Atomic Bombs: How a Simple Slip in Los Alamos Turned Deadly

What happened in Los Alamos during World War Two is under a lot of scrutiny these days. There was the TV show, then there was the national park, and now President Obama is going to Hiroshima to confront, in some way, the legacy of the scientists who built the first atomic bomb. A story in this week's New Yorkerreally emphasizes the dramatic pull of Los Alamos, recounting a terrifying story of a dropped screwdriver nearly a year after the bombs fell.

Louis Slotin was a Canadian physicist who had worked through the war at Los Alamos, where his job was criticality testing, which involved bringing fissile materials to near-critical levels to establish their critical mass values. It was incredibly dangerous work, but by 1946 Slotin was already an expert. He had assembled the Trinity test bomb, and in fact had wanted to leave Los Alamos much earlier. Only his expertise in the physical work of criticality kept him tied to New Mexico. On May 21 he was finally training a replacement, Alvin C. Graves.

A recreation of the Slotin criticality testing.

The act of criticality testing was referred to as "tickling the dragon's tail," a phrase which came from Richard Feynmann's observation on the obvious dangers involved. All Slotin would do was lower a half-shell of beryllium into a live nuclear core and stop short of dropping it in all the way. This would create a series of extremely weak nuclear chain reactions, from which the scientists could determine criticality. He'd jimmy a screwdriver between the beryllium and the core to keep them from interacting. It was dangerous work which had become, to a certain extent, rote.

After the accident, Louis Slotin quickly drew a sketch of where people had been standing in the room, to his best memory.

Then Slotin's screwdriver slipped. Suddenly, quadrillions of fission reactions were happening inside this one room. Far fewer than an actual bomb, but enough to be taken very seriously. Slotin acted as quickly as humanly possible to contain the reaction, but the damage had been done. What happened next allowed scientists to learn more about fallout.

Slotin died several agonizing days later. A memo was later issued suggesting that future criticality experiments use remote controls. Slotin's story remains a very small one in the face of the widespread death wrought by the bomb, but it shows how even those who were convinced they were able to control its power, could, through the slightest of errors, sign away their lives.

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